The existing IEEE 802.11n has defined stream mapping applicable to a MIMO system, and a stream mapping method for multiple streams is considered in the solution of the stream mapping. A stream mapper defined in IEEE 802.11n is used to map succeeding s bits to different space streams in a round-robin mode, where s is defined as s=max{Nbpsc(si)/2,1}, and a result of the IEEE 802.11n mapping is shown in FIG. 1.
Such a mapping method in the prior art will cause serious performance degradation to a multi-stream beamforming system at high-order modulation and a high code rate.